text: let zoomed_in = false;
  
  exports.is_zoomed_in = function () {
      return zoomed_in;
  };
  
  function zoom_in() {
      const stream_id = topic_list.active_stream_id();
  
      popovers.hide_all_except_sidebars();
      topic_list.zoom_in();
      stream_list.zoom_in_topics({
          stream_id: stream_id,
      });
  
      zoomed_in = true;
  }
  
  exports.zoom_out = function () {
      const stream_li = topic_list.get_stream_li();
  
      popovers.hide_all_except_sidebars();
      topic_list.zoom_out();
      stream_list.zoom_out_topics();
  
      if (stream_li) {
          stream_list.scroll_stream_into_view(stream_li);
      }
  
      zoomed_in = false;
  };
  
  exports.clear_topics = function () {
      const stream_li = topic_list.get_stream_li();
  
      topic_list.close();
  
      if (zoomed_in) {
          stream_list.zoom_out_topics();
  
          if (stream_li) {
              stream_list.scroll_stream_into_view(stream_li);
          }
      }
  
      zoomed_in = false;
  };
  
  exports.initialize = function () {
      $('#stream_filters').on('click', '.show-more-topics', function (e) {
          zoom_in();
  
          e.preventDefault();
          e.stopPropagation();
      });
  
      $('.show-all-streams').on('click', function (e) {
          exports.zoom_out();
  
          e.preventDefault();
          e.stopPropagation();
      });
  };
  
  window.topic_zoom = exports;
  